HEP Phenomenology·hep-ph
20 papers—15 primary·5 cross-listed·reconstructed*
We review Standard-Model evaluations of hadronic contributions to the muon anomalous magnetic moment . Most space is devoted to the hadronic vacuum polarization contribution, in view of the discrepancy between the data-based dispersive evaluation and the lattice evaluation by the BMW collaboration.
Yidian Chen🇨🇳 · Danning Li🇨🇳 · Mei Huang🇨🇳
We investigate inhomogeneous chiral condensation under rotation considering finite size effects and boundary conditions in the holographic QCD model. The rotational suppression effect determined by is confirmed in the holographic model which is not influenced by the boundary conditions. For chiral condensation at the center, it is found that under Neumann boundary condition the finite size exhibits two opposite effects, i.e., catalysis at high temperatures and inverse catalysis at low temperatures. In contrast, under Dirichlet boundary condition, the effect of finite size on condensation is inverse catalysis, and small size induces a phase transition from inhomogeneous to homogeneous phase. The temperature-angular velocity phase diagrams of QCD are obtained for different boundary conditions and sizes, and it is found that the critical temperature decreases with angular velocity.
Yifan Chen🇩🇰 · Chunlong Li🇨🇳 · Yosuke Mizuno🇨🇳 · Jing Shu🇨🇳 · Xiao Xue🇩🇪 · Qiang Yuan🇨🇳 · Yue Zhao🇺🇸 · Zihan Zhou🇺🇸
An axion cloud surrounding a supermassive black hole can be naturally produced through the superradiance process. Its existence can be examined by the axion induced birefringence effect. It predicts an oscillation of the electric vector position angle of linearly polarized radiations. Stringent constraints of the existence of the axion in a particular mass window has been obtained based on the recent Event Horizon Telescope measurement on M87. The future Very-Long-Baseline Interferometry (VLBI) observations will be able to measure the vicinity of many supermassive black holes, thus it opens the possibility to search for the existence of axions in a wide mass regime. In this paper, we study how different black hole properties and accretion flows influence the signatures of the axion induced birefringence. We include the impacts of black hole inclination angles, spins, magnetic fields, plasma velocity distributions, the thickness of the accretion flows. We pay special attention to characterize the washout effects induced by the finite thickness of the accretion flows and the lensed photons. Based on this study, we give prospects on how to optimize the axion search using future VLBI observations, such as the next-generation Event Horizon Telescope, to further increase the sensitivity.
We present an overview of the recent neutral current decays focusing on the deviations with respect to the Standard Model predictions that are observed in transitions, and discuss their implications for new physics scenarios in a model-independent way by means of global statistical fits. The prospects for future discoveries in the individual channels, in particular using the theoretically clean observables are also addressed.
Ekta Chaubey🇮🇹 · Ina Hönemann🇩🇪 · Stefan Weinzierl🇩🇪
We consider the full set of master integrals with internal top-and -propagators contributing to the three-loop Higgs self-energy diagrams of order . We split the master integrals into a system relevant to the Feynman diagrams proportional to the product of Yukawa couplings and the complement. For both systems we define master integrals of uniform weight, such that the associated differential equation is in -factorised form. The occurring square roots are rationalised and all master integrals are expressible in multiple polylogarithms.
Stefano Catani🇮🇹 · Prasanna K. Dhani🇮🇹
The singular behaviour of QCD squared amplitudes in the collinear limit is factorized and controlled by splitting kernels with a process-independent structure. We use these kernels to define collinear functions that can be used in QCD resummation formulae of hard-scattering observables. Different collinear functions are obtained by integrating the splitting kernels over different phase-space regions that depend on the hard-scattering observables of interest. The collinear functions depend on an auxiliary vector that can be either light-like or time-like . In the case of transverse-momentum dependent (TMD) collinear functions, we show that the use of a time-like auxiliary vector avoids the rapidity divergences, which are instead present if . The perturbative computation of the collinear functions lead to infrared (IR) divergences that can be properly factorized with respect to IR finite functions that embody the logarithmically-enhanced collinear contributions to hard-scattering cross sections. We evaluate various collinear functions and their dependence at . We compute the azimuthal-correlation component of the TMD collinear functions at , and we present the results of the contribution of linearly-polarized gluons to transverse-momentum resummation formulae. Beyond the collinear functions of initial-state colliding partons are process dependent, as a consequence of the violation of strict collinear factorization of QCD squared amplitudes.
Pallabi Parui🇮🇳 · Sourodeep De🇮🇳 · Ankit Kumar🇮🇳 · Amruta Mishra🇮🇳
The masses of the and states of heavy quarkonia are investigated in the magnetized, asymmetric nuclear medium, accounting for the Dirac sea effects, using a combined approach of chiral effective model and QCD sum rule method. These are calculated from the in-medium scalar and twist-2 gluon condensates, calculated within the chiral model. The gluon condensate is simulated through the scalar dilaton field, introduced in the model through a scale-invariance breaking logarithmic potential. Considering the scalar fields to be classical, the dilaton field, , the non-strange isoscalar, , strange isoscalar, and non-strange isovector, ) fields, are obtained by solving their coupled equations of motion, as derived from the chiral model Lagrangian. The effects of magnetic field due to the Dirac sea as well as the Landau energy levels of protons, and the non-zero anomalous magnetic moments of the nucleons are considered in the present study. In presence of an external magnetic field, there is also mixing between the longitudinal component of the vector meson and pseudoscalar meson (PV mixing) in both quarkonia sectors, leading to a rise (drop) of the masses of ) and ) states. These might show in the experimental observables, e.g., the dilepton spectra in the non-central, ultra-relativistic heavy ion collision experiments at RHIC and LHC, where the produced magnetic field is huge.
Yann Mambrini🇫🇷 · Keith A. Olive🇺🇸 · Jiaming Zheng🇨🇳
Dark matter may only interact with the visible sector efficiently at energy scales above the inflaton mass, such as the Planck scale or the grand unification scale. In such a scenario, the dark matter is mainly produced out of equilibrium during the period of reheating, often referred to as UV freeze-in. We evaluate the abundance of the dark matter generated from bremsstrahlung off the inflaton decay products assuming no direct coupling between the inflaton and the dark matter. This process generally dominates the production of dark matter for low reheating temperatures where the production through the annihilations of particle in the thermal plasma becomes inefficient. We find that the bremsstrahlung process dominates for reheating temperatures GeV, and produces the requisite density of dark matter for a UV scale GeV. As examples, we calculate numerically the yield of the dark matter bremsstrahlung through gravitation and dimension-6 vector portal effective interactions.
Karim Benakli🇫🇷 · Mark Goodsell🇫🇷 · Wenqi Ke🇫🇷 · Pietro Slavich🇫🇷
We investigate the conditions for alignment in Dirac Gaugino models with minimal matter content. This leads to several scenarios, including an aligned Dirac Gaugino NMSSM that allows a light singlet scalar. We then investigate the compatibility of minimal Dirac Gaugino models with an enhanced W boson mass, using a new precise computation of the quantum corrections included in the code SARAH 4.15.0.
The physics content of the QGSJET-III Monte Carlo generator of high energy hadronic collisions is discussed. New theoretical approaches implemented in QGSJET-III are addressed in some detail and a comparison to alternative treatments of other cosmic ray interaction models is performed. Calculated characteristics of cosmic ray-induced extensive air showers are presented and differences between the respective results of QGSJET-III and other models are analyzed. In particular, it is demonstrated that those differences are partly caused by severe deficiencies of the other interaction models.
M. J. Herrero🇪🇸 · R. A. Morales🇦🇷
In this work we present the computation of the one-loop electroweak radiative corrections to the scattering process within the context of the Higgs Effective Field Theory (HEFT). We assume that the fermionic interactions are like in the Standard Model, whereas the Beyond Standard Model interactions in the bosonic sector are given by the Electroweak Chiral Lagrangian. The computation of the one-loop amplitude and the renormalization program is performed in terms of the involved one-particle-irreducible functions (1PI) and using covariant gauges. The renormalization of 1PI functions at arbitrary external momenta is a more ambitious program than just renormalizing the amplitude with on-shell external legs and it has the advantage that they can be used in several scattering amplitudes. In fact, we use here some of the 1PI functions already computed in our previous work (devoted to ). We will complement them here with the computation of the new 1PI functions required for . From this renormalization procedure we will also derive the full set of renormalized coefficients of the EChL that are relevant for this scattering process. In the last part, we will present the numerical results for the EChL predictions of the one-loop level cross section, , as a function of the center of mass energy, showing the relative size of the one-loop radiative corrections respect to the tree level prediction in terms of the EChL coefficients. The results of the one-loop corrections to for the SM case will be also presented, for comparison with the EChL case, following the same computational method, i.e., by means of the renormalization of 1PI functions.
Suman Kumbhakar🇨🇦 · Ria Sain🇮🇳 · Juhi Vardani🇮🇳
A number of measurements in decays induced by the semileptonic and transitions hint towards a possible role of new physics in both sectors. Motivated by these anomalies, we investigate the lepton flavor violating decays. We calculate the two-fold angular distribution of decay in presence of vector, axial-vector, scalar and pseudo-scalar new physics interactions. We then compute the branching fraction and lepton forward-backward asymmetry in the framework of vector leptoquark which is a viable solution to the current anomalies. We find that the upper limits are and at C.L.
Taiki Bessho🇯🇵 · Yuji Ikeda🇯🇵 · Wen Yin🇯🇵
Infrared spectroscopy has been developed significantly. In particular, infrared photons can be measured with high spectral and angular resolution in state-of-art spectrographs. They are sensitive to monochromatic photons due to the decay and annihilation of particles beyond the Standard Model, such as dark matter (DM), while insensitive to background photons that form a continuous spectrum. In this paper, we study the indirect detection of the DM decaying into infrared light using infrared spectrographs. In particular, we show that serious thermal and astrophysical noises can be overcome. As concrete examples, the Warm INfrared Echelle spectrograph to Realize Extreme Dispersion and sensitivity (WINERED) installed at the Magellan Clay 6.5m telescope and Near-Infrared Spectrograph (NIRSpec) at the James Webb Space Telescope (JWST) are discussed. We show that a few hours of measurements of a faint dwarf spheroidal galaxy with WINERED (NIRSpec-like spectrograph) in the Magellan telescope (JWST) can probe an axion-like particle DM in the mass range eV (eV) with a photon coupling . Complemental approaches, taking advantage of the high resolutions, such as the measurement of the Doppler shift of the signal photon lines and the possible search of the DM decay around the Milky Way galaxy center with Infrared Camera and Spectrograph (IRCS) at 8.2m Subaru telescope, are also presented.
Manuel A. Buen-Abad🇺🇸 · Zackaria Chacko🇺🇸 · Can Kilic🇺🇸 · Gustavo Marques-Tavares🇺🇸 · Taewook Youn🇺🇸
We propose a new interacting dark sector model, Stepped Partially Acoustic Dark Matter (SPartAcous), that can simultaneously address the two most important tensions in current cosmological data, the and problems. As in the Partially Acoustic Dark Matter (PAcDM) scenario, this model features a subcomponent of dark matter that interacts with dark radiation at high temperatures, suppressing the growth of structure at small scales and thereby addressing the problem. However, in the SPartAcous model, the dark radiation includes a component with a light mass that becomes non-relativistic close to the time of matter-radiation equality. As this light component annihilates away, the remaining dark radiation heats up and its interactions with dark matter decouple. The heating up of the dark sector results in a step-like increase in the relative energy density in dark radiation, significantly reducing the tension, while the decoupling of dark matter and dark radiation ensures that the power spectrum at larger scales is identical to CDM.
Roshan Mammen Abraham🇺🇸 · Dorival Gonçalves🇺🇸
The angular moments for the boson can be used as analyzers for the underlying production dynamics for the and processes. In this manuscript, we derive these angular moments at leading and next-to-leading order in QCD at the LHC. We show that these observables work as efficient probes to beyond the Standard Model effects, considering the Standard Model Effective Field theory framework. Remarkably, we observe that these probes unveil blind directions to CP-odd operators, providing sizable new physics sensitivity at the 14 TeV LHC with 3 ab of data.
After playing a pivotal role in the birth of the Standard Model in the 70's, the study of charm physics has undergone a revival during the last decade, triggered by a wealth of precision measurements from the charm and factories, and from the CDF and especially the LHCb experiments. In this article, we sum up how the unique phenomenology of charmed hadrons can be used to test the Standard Model and we review the latest measurements performed in this field by the LHCb experiment. These include the historic first observations of violation and of a nonzero mass difference between the charmed neutral-meson mass eigenstates, the most precise determination of their decay-width difference to date, and a search for time-dependent violation reaching the unprecedented precision of . These results challenge our comprehension of nonperturbative strong interactions, and their interpretation calls for further studies on both the theoretical and experimental sides. The upcoming upgrades of the LHCb experiment will play a leading role in this quest.
Oleg Antipin🇭🇷 · Jahmall Bersini🇭🇷 · Pantelis Panopoulos🇭🇷
We extend the fixed-charge semiclassical method by computing anomalous dimensions of fixed-charge scalar operators in models with Yukawa interactions. In particular, we discuss the Nambu-Jona-Lasinio-Yukawa theory as well as an asymptotically safe gauge-Yukawa model in four dimensions. In the weakly coupled regime, we cross-check our results to the respective maximum known orders of perturbation theory in these models and predict higher order terms for future comparisons with other computational methods. In the strongly coupled regime, we match our results to the predictions of the large-charge effective field theory which can be compared to future Monte Carlo and lattice studies.
Théo Simon🇫🇷 · Pierre Zhang🇨🇳 · Vivian Poulin🇫🇷 · Tristan L. Smith🇺🇸
We assess the robustness of CDM results from the full-shape analysis of BOSS power spectrum using the one-loop prediction of the Effective Field Theory of Large-Scale Structure (EFTofLSS). The public likelihoods PyBird and CLASS-PT lead to results in agreement only at the level, despite the fact that they are derived from the same BOSS dataset and theory model. We perform a thorough comparison of the various analyses choices made between the two pipelines, and identify that the differences come from the choice of prior on the EFT parameters, dubbed "West-coast" (WC) and "East-coast" (EC) prior, respectively associated to PyBird and CLASS-PT. In particular, because posteriors are non-Gaussian, projection effects from the marginalization over the EFT parameters shift the posterior mean of the cosmological parameters with respect to the best-fit up to in the WC prior and up to in the EC prior. We quantify that best-fit cosmological parameters extracted from BOSS given the two prior choices are consistent at . The consistency improves to when doubling the prior widths. While this reveals that current EFT analyses are subject to prior effects, we show that cosmological results obtained in combination with CMB, or from forthcoming large-volume data, are less sensitive to those effects. In addition, we investigate differences between BOSS measurements. We find broad agreements across all pre-reconstructed measurements considered (), but the two available BOSS post-reconstructed measurements in Fourier space, once combined with the EFT full-shape analysis, lead to discrepant Hubble parameter at . Given the various effects we discuss, we argue that the clustering amplitude measured with BOSS is not in statistical tension with that inferred from Planck under CDM.
Théo Simon🇫🇷 · Pierre Zhang🇨🇳 · Vivian Poulin🇫🇷 · Tristan L. Smith🇺🇸
Analyses of the full shape of BOSS DR12 power spectrum using the one-loop prediction from the Effective Field Theory of Large-Scale Structure (EFTBOSS) have led to new constraints on extensions to the CDM model, such as Early Dark Energy (EDE) which has been suggested as a resolution to the "Hubble tension". In this paper, we re-assess the constraining power of the EFTBOSS on EDE in light of a correction to the normalization of BOSS window functions. Overall we find that constraints from EFTBOSS on EDE are weakened, and represent a small change compared to constraints from Planck and the conventional BAO/ measurements. The combination of Planck data with EFTBOSS provides a bound on the maximal fractional contribution of EDE at 95% C.L. (compared to with the incorrect normalization, and without full-shape data) and the Hubble tension is reduced to . However, the more extreme model favored by an analysis with just data from the Atacama Cosmology Telescope is disfavored by the EFTBOSS data. We also show that the updated Pantheon+ Type Ia supernova analysis can slightly increase the constraints on EDE. Yet, the inclusion of the SN1a magnitude calibration by SH0ES strongly increases the preference for EDE to above , yielding around the redshift . Our results demonstrate that EFTBOSS data (alone or combined with Planck data) do not exclude the EDE resolution of the Hubble tension.
Masamune Oguri🇯🇵 · Volodymyr Takhistov🇯🇵 · Kazunori Kohri🇯🇵
Stellar-mass primordial black holes (PBHs) from the early Universe can directly contribute to the gravitational wave (GW) events observed by LIGO, but can only comprise a subdominant component of the dark matter (DM). The primary DM constituent will generically form massive halos around seeding stellar-mass PBHs. We demonstrate that gravitational lensing of sources at cosmological (Gpc) distances can directly explore DM halo dresses engulfing PBHs, challenging for lensing of local sources in the vicinity of Milky Way. Strong lensing analysis of fast radio bursts detected by CHIME survey already starts to probe parameter space of dressed stellar-mass PBHs, and upcoming searches can efficiently explore dressed PBHs over mass-range and provide a stringent test of the PBH scenario for the GW events. Our findings establish a general test for a broad class of DM models with stellar-mass PBHs, including those where QCD axions or WIMP-like particles comprise predominant DM. The results open a new route for exploring dressed PBHs with various types of lensing events at cosmological distances, such as supernovae and caustic crossings.
* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.